One afternoon in late March, in their offices overlooking a courtyard in downtown Helsinki, Jaakko Iisalo, a games designer who had been at Rovio since 2006, showed them a screenshot. He had pitched hundreds in the two months before. This one showed a cartoon flock of round birds, trudging along the ground, moving towards a pile of colourful blocks. They looked cross. "People saw this picture and it was just magical," says [Niklas Hed, who co-runs the company]. Eight months and thousands of changes later, after nearly abandoning the project, Niklas watched his mother burn a Christmas turkey, distracted by playing the finished game. "She doesn't play any games. I realised: this is it."